The most likely time an abuser will fatally harm their SO is when they are leaving them. You should never have gone back alone.
Do not put yourself in harms way again. Take a police officer or a couple of strong friends if you have to be in his presence again.
Actually, contact your local women's shelter or domestic violence center and ask questions and get involved in their support groups. You may leave, and that is just the start...but you have learned some coping behaviors that are not healthy, you need to unlearn and gain a "normal" perspective on what a healthy relationship is.....This is imperative.....Otherwise you will keep choosing the same type of abusive man. Do not even date until you get help.
Myths & Facts about Domestic Violence | Domestic Violence Intervention Program